1. Field of the Invention
This invention relates generally to the field of lamps or light sources designed for insertion into existing A.C. or D.C. sockets and drawing their energy therefrom. More particularly, it relates to a lamp having a generally cylindrical open encasement suited for use with Light Emitting Diodes (LEDs), allowing them to be more readily used in standard lamp sockets and, more particularly, as replacements for what are commonly referred to as "miniature lamps".
2. Description of the Prior Art
Electrically powered lamps in all sizes are, of course, an ubiquitous part of current technology. In one category alone, referred to in the art area as "miniature lamps", there are (including variations in size) more than two hundred (200) incandescent configurations intended for various specialized uses. The encasement described herein is expandable to meet the requirements of larger lamps that produce more light and consume more electricity. However, it is more specifically intended to facilitate the replacement of most current miniature lamps having an incandescent filament suspended in a clear bulb as their light producing element with lamps utilizing an LED as their light producing element.
The advantages inherent in such replacement are principally derived from the LED's greater efficiency (in terms of energy consumption) and durability when compared to incandescents. The incandescent consumes copious amounts of energy, converting a very high percentage of same into waste heat. LED's consume very little energy in proportion to the light produced and, conversely, produce very little waste heat. Further, the incandescent is, by its nature, extremely fragile when compared with LED light sources. First, it is sensitive to excessive amperages, which will burn out the filament. Second, it is sensitive, both because of its glass globe and the thin filament it utilizes as its light producing element, to rough handling, and breaks easily. The filament is especially prone to this problem due to weakening caused by the excessive heating of its metal during operation. Finally, most incandescents produce only white light. Many applications, particularly in military areas, require the use of low intensity colored light. LEDs generally produce such light, but current incandescent sources must be reduced in intensity and colored by filters to produce same. Thus, in these areas, as in many others, the incandescent is a wasteful alternative when compared with the LED.
Two U.S. patents issued for LED lamps are representative of those seeking to exploit these features: U.S. Pat. No. 4,211,955 issued to Stephen W. Ray and U.S. Pat. No. 4,727,289 issued to Akio Uchida. The Ray patent describes an area-illuminating solid state lamp having the appearance of a standard incandescent light bulb with LEDs enclosed within a globe of solid translucent plastic. It also illustrates the two features necessary for the utilization of LEDs in this application--a current adjustment element (in this case featuring a rectifier as well as a resistor) and a generally cylindrical base capable of interfacing with standard incandescent light sockets. However, it is seriously restricted in use because of the closed nature of its encasement. The performance of LEDs degrades as temperature (generated by current reducing/control elements) becomes elevated. The closed nature of the Ray device causes the accumulation of waste heat generated by the device. A solution to this problem is attempted by Uchida, who utilizes an annular-shaped resistor fitted around the stem of the lamp as a means of overcoming this problem; however, the solution utilized herein is far simpler, and leads to a device that overcomes the temperature build-up problems of prior patents, is far simpler and less expensive to manufacture, and has numerous additional advantages as set forth below.